The TPDDL has now developed the capacity to diagnose Pierce's Disease (PD) of grapes by applying the most progressive and reliable laboratory methods. These methods have been tested in a number of projects sponsored by the Texas Pierce's Disease Research and Education Program and have been successfully applied in those projects to confirm PD throughout the State. Growers will have the option to select the protocol they prefer, and will be expected to fully participate in the diagnostic process by filling out the proper forms and following some simple sampling directions. This system has been developed to provide grape growers with the best possible diagnostic results.
The diagnosis of Pierce’s disease can be a difficult problem. The bacterium,
Xylella fastidiosa, may be unevenly distributed in host vines and typical symptoms may not be an accurate measure of the degree of colonization by the pathogen. Therefore, it is important that samples be collected by following the instructions on the Pierce’s Disease Diagnosis Form (
Form TPDDL 1004). It will be noted that two laboratory assay protocols are available. They are ELISA (Enzyme Linked Immunosorbent Assay) and QRT-PCR (Quantitative Real Time - Polymerase Chain Reaction). Each has advantages and disadvantages regarding sensitivity, time to obtain results, and cost. For further information on how to collect samples, ship them, and select assay methods, refer to the instructions on the form.
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D. Appel.
